Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, May 16, 1995 TAG: 9505160056
SECTION: EXTRA PAGE: 1 EDITION: METRO
SOURCE: JANE BRODY
DATELINE: LENGTH: Long
After years of advice to reduce fat intake to 30 percent of daily calories and to limit cholesterol consumption to less than 300 milligrams a day, the public learns that a British scientist has concluded after reviewing the best available studies that such a diet has a minimal - if any - effect on the incidence of heart disease and coronary death rates.
After being told that any amount of exercise is bound to be beneficial, the public learns that a Harvard researcher has found that only vigorous exercise prolonged the lives of Harvard alumni.
After being told to eat more seafood to prevent heart disease, the public learns of a study of thousands of male doctors that found no such protection.
Whom are people to believe?
The time has come to start applying logic and good sense to these questions: to decide exactly what individuals hope to achieve and then adopt living habits commensurate with those goals.
By now, it should be obvious that no one activity, food or attitude can guarantee untarnished golden years and that the surest path to a long and healthy life comes from a combination of factors that includes diet, exercise and stress management along with avoidance of health-robbing habits like smoking and excessive drinking.
To make a real dent in disease, disability and premature death, people need to accept the whole package, not just one small part.
Some of the best clues to longevity come from studies of long-lived populations that have, at least in the past, largely avoided the costly chronic and life-threatening diseases that afflict Americans in epidemic proportions.
Further clues come from an increased understanding of the biochemical machine that is the human body, a machine that has not changed in any substantive way in the 4 million years since it evolved.
Finally, while more research is clearly needed, especially on the factors that most influence longevity in women, there have been quite a few reliable studies from which sound guidance can be gleaned.
Homo sapiens evolved as gatherers and sometime hunters. As best as anthropologists and anatomists can determine, humans were designed to be primarily vegetarians with occasional feasts of meat and other animal foods.
The early human diet was necessarily very low in fat: rich in fruits and vegetables and sparing in low-fat animal protein from lean and sinewy wild animals, not cattle, hogs and chickens raised on corn and grain and confined to pens where they put on lots of fat. And early humans were an active bunch, working hard physically every day to obtain food and shelter.
Until this century, life expectancy rarely exceeded the reproductive years, with most people dying of infectious diseases. The advent of modern sanitation, immunizations and antibiotics brought most lethal infections under control and the industrial revolution eliminated the need for all that activity just to stay alive.
As American affluence increased, people not only lived longer but also higher on the hog. They ate more animal protein and more fat, they became increasingly sedentary, they got fatter and fatter and they took up cigarette smoking as a major means of stress control.
Japan has served as a living laboratory. Until recently the Japanese, who were largely free of heart disease and breast and lung cancer and who still live longer than Americans do, consumed a diet that closely resembled the early human diet and contained less than half the fat Americans now eat.
With rising affluence, the Japanese began eating more meat and fat and Japanese men took up smoking with a vengeance. As expected, the Japanese rate of heart disease began rising and lung and other smoking-related cancers are likely to follow.
In a carefully designed study, Dr. Dean Ornish of the Preventive Medicine Research Institute in Sausalito, Calif., proved the value of a diet very low in fat and rich in vegetable foods in patients already seriously afflicted with heart disease.
His plan, a rather strict vegetarian one that includes nonfat dairy products and egg whites but excludes all oils, calls for 10 percent of calories from fat and only 5 milligrams of cholesterol a day.
Along with a daily regime of moderate exercise and meditation and other techniques to reduce stress, the approach not only vastly improved participants' coronary risk factors, but it also significantly reversed arterial clogging and increased coronary blood flow.
The average, still-healthy American is unlikely to need a diet as strict as Ornish's to remain healthy, but the message from his studies is clear: for most people who hope to live healthfully into their 80s, their diets need serious fat (and calorie) stripping.
Without question, cigarettes and other forms of tobacco must go, and if alcohol is consumed, it should be only in moderation - no more than one drink a day for women or two drinks for men.
And, last but hardly least, the human body needs regular physical activity. How vigorous must that activity be? That depends on the individual and what he or she hopes to achieve.
Experts agree that any kind and amount of exercise is better than none. Regular physical activity - even just walking or working around the house or garden for an hour a day for a person who was formerly sedentary - can help one reduce harmful blood fats, lower blood pressure, normalize blood sugar, relieve stress, shed extra pounds and preserve bone mass.
But the experts also agree that while some exercise is good, more is better. Up to what point, they have not yet determined. Although studies have shown that the people who exercise the longest and hardest are likely to remain alive and healthy the longest as well, they have also shown that moderate exercise has undeniable health and longevity benefits.
The new study of Harvard men did not examine longevity in moderate exercisers separately from that in men who did little or no exercise and for this reason may have failed to show a longevity increase from moderate exercise.
As for a failure in the latest study to find a benefit from eating fish or taking fish oils, this does not mean that eating seafood often cannot help to lower the risk of developing heart disease or cancer or obesity.
There are several potential pitfalls in that study (including the possibility that most of the fish the men ate was low in the oils believed to be protective) that could account for its negative finding when several other studies have suggested otherwise.
The best lesson to learn from the new finding on fish is not to change one's living habits on the basis of one study. For a finding to become a fact, it must be replicated by independent scientists in different groups of people and it should have a demonstrable biological explanation.
Meanwhile, for a currently healthy person, moderation appears to be the wisest course.
Follow a diet low in fat (15 to 20 percent of calories from fat seems reasonable and likely to be beneficial) and rich in grains and other starches, fruits and vegetables, and get regular, preferably daily, exercise, alternating between two or three moderate to vigorous activities like brisk walking, cycling, swimming laps and strength training.
by CNB